Instability footwear sole



FIG. 1 is a right side view of an instability footwear sole showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the design. 

CLAIM The ornamental design for an instability footwear sole, as shown and described. 